NOAO >   Observing Info >   Approved Programs >   2002A-0097

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Proposal Information for 2002A-0097


PI: Eric Sandquist, San Diego State University, erics@mintaka.sdsu.edu
Address: 5500 Campanile Drive, San Diego, CA 92182, USA

CoI: Matthew Shetrone, McDonald Observatory

Title: Towards a Complete Spectroscopic Survey of M67 Blue Stragglers

Abstract: Binary stars are one of the most important drivers of the dynamics of a star cluster. Because blue straggler stars are created via binary mass transfer or stellar collisions and because they are relatively bright, blue stragglers are among the most easily observable consequences of the presence of binaries in a cluster. Theoretical studies predict that surface abundances can distinguish between blue stragglers formed by mass transfer and by collisions, and two small spectroscopic studies of the open cluster M67 have observed differences in C/N and O/N ratios and s-process abundances from straggler to straggler. Because the relative numbers of mass-transfer stragglers and collisionally-formed stragglers are an indicator of the frequency of strong gravitational interactions between stars in a cluster, a complete survey of the stragglers would constrain the recent dynamical history of the cluster. We therefore propose to conduct high-resolution spectroscopy of faint blue stragglers in M67 as part of an ongoing multi- observatory project to study all of the identifiable blue stragglers in the cluster.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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